Last week we happened across a great "living math" book because it was recommended supplemental reading in the The Story of the World history program. In the story, One Grain Of Rice: A Mathematical Folktale, a young girl is suggests as a reward that she receive one grain of rice. When this is declared inadequate she suggests that receive rice for thirty days and that each day the quantity she receives shall be double the quantity of the day before. She receives one grain the first day, two the second, four the third, eight the fourth, and so on. After reading this. The boys suggest that we see if the book as accurate as well as determine the how much rice she received on the last day and in total. (I had abstained from reading them the last page that had a chart with all of that information.)
I played the role of administrative assistant. The boys took turns creating and solving the equations while I did the writing. A child who is a more persistent writer than either of mine could do this completely on their own.
It was difficult to add the longer categories, such as the units, at the end. The dot board would have been good here if it were set up for numbers bigger than 99,999. We penciled in intermediate sums along the edge of the paper.